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<h2><span class="refentrytitle">Macro BOOST_TYPE_INDEX_REGISTER_RUNTIME_CLASS</span></h2>
<p>BOOST_TYPE_INDEX_REGISTER_RUNTIME_CLASS — Macro used to make a class compatible with boost::typeindex::runtime_cast. </p>
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<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2>
<div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: &lt;<a class="link" href="boost_typeindex_header_reference.html#header.boost.type_index.runtime_cast.register_runtime_class_hpp" title="Header &lt;boost/type_index/runtime_cast/register_runtime_class.hpp&gt;">boost/type_index/runtime_cast/register_runtime_class.hpp</a>&gt;

</span>BOOST_TYPE_INDEX_REGISTER_RUNTIME_CLASS(base_class_seq)</pre></div>
<div class="refsect1">
<a name="id-1.3.43.8.8.4.4"></a><h2>Description</h2>
<p>BOOST_TYPE_INDEX_REGISTER_RUNTIME_CLASS generates a virtual function in the current class that, when combined with the supplied base class information, allows boost::typeindex::runtime_cast to accurately convert between dynamic types of instances of the current class.</p>
<p>BOOST_TYPE_INDEX_REGISTER_RUNTIME_CLASS also adds support for boost::typeindex::type_id_runtime by including BOOST_TYPE_INDEX_REGISTER_CLASS. It is typical that these features are used together, but in the event that BOOST_TYPE_INDEX_REGISTER_CLASS is undesirable in the current class, BOOST_TYPE_INDEX_IMPLEMENT_RUNTIME_CAST is provided.</p>
<p><span class="bold"><strong>Example:</strong></span> </p>
<pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">base1</span> <span class="special">{</span>
    <span class="identifier">BOOST_TYPE_INDEX_REGISTER_RUNTIME_CLASS</span><span class="special">(</span><span class="identifier">BOOST_TYPE_INDEX_NO_BASE_CLASS</span><span class="special">)</span>
    <span class="keyword">virtual</span> <span class="special">~</span><span class="identifier">base1</span><span class="special">(</span><span class="special">)</span><span class="special">;</span>
<span class="special">}</span><span class="special">;</span>

<span class="keyword">struct</span> <span class="identifier">base2</span> <span class="special">{</span>
    <span class="identifier">BOOST_TYPE_INDEX_REGISTER_RUNTIME_CLASS</span><span class="special">(</span><span class="identifier">BOOST_TYPE_INDEX_NO_BASE_CLASS</span><span class="special">)</span>
    <span class="keyword">virtual</span> <span class="special">~</span><span class="identifier">base2</span><span class="special">(</span><span class="special">)</span><span class="special">;</span>
<span class="special">}</span><span class="special">;</span>

<span class="keyword">struct</span> <span class="identifier">derived1</span> <span class="special">:</span> <span class="identifier">base1</span> <span class="special">{</span>
    <span class="identifier">BOOST_TYPE_INDEX_REGISTER_RUNTIME_CLASS</span><span class="special">(</span><span class="special">(</span><span class="identifier">base1</span><span class="special">)</span><span class="special">)</span>
<span class="special">}</span><span class="special">;</span>

<span class="keyword">struct</span> <span class="identifier">derived2</span> <span class="special">:</span> <span class="identifier">base1</span><span class="special">,</span> <span class="identifier">base2</span> <span class="special">{</span>
    <span class="identifier">BOOST_TYPE_INDEX_REGISTER_RUNTIME_CLASS</span><span class="special">(</span><span class="special">(</span><span class="identifier">base1</span><span class="special">)</span><span class="special">(</span><span class="identifier">base2</span><span class="special">)</span><span class="special">)</span>
<span class="special">}</span><span class="special">;</span>

<span class="special">...</span>

<span class="identifier">base1</span><span class="special">*</span> <span class="identifier">pb1</span> <span class="special">=</span> <span class="identifier">get_object</span><span class="special">(</span><span class="special">)</span><span class="special">;</span>
<span class="keyword">if</span><span class="special">(</span><span class="identifier">derived2</span><span class="special">*</span> <span class="identifier">pb2</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">typeindex</span><span class="special">::</span><span class="identifier">runtime_cast</span><span class="special">&lt;</span><span class="identifier">derived2</span><span class="special">*</span><span class="special">&gt;</span><span class="special">(</span><span class="identifier">pb1</span><span class="special">)</span><span class="special">)</span> <span class="special">{</span>
    <span class="identifier">assert</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">typeindex</span><span class="special">::</span><span class="identifier">type_id_runtime</span><span class="special">(</span><span class="special">*</span><span class="identifier">pb1</span><span class="special">)</span><span class="special">)</span> <span class="special">==</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">typeindex</span><span class="special">::</span><span class="identifier">type_id</span><span class="special">&lt;</span><span class="identifier">derived2</span><span class="special">&gt;</span><span class="special">(</span><span class="special">)</span><span class="special">)</span><span class="special">;</span>
<span class="special">}</span>
</pre>
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<td><p><span class="term">Parameters:</span></p></td>
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<td><p><span class="term"><code class="computeroutput">base_class_seq</code></span></p></td>
<td><p>A Boost.Preprocessor sequence of the current class' direct bases, or BOOST_TYPE_INDEX_NO_BASE_CLASS if this class has no direct base classes. </p></td>
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<td align="right"><div class="copyright-footer">Copyright © 2012-2021 Antony Polukhin<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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